topic imx6sl uart rts/cts in i.MX Processors

imx6sl uart rts/cts

yan2anfei — Mon, 23 Jul 2018 09:44:45 GMT

hi ,

my chip is imx6sl, I use uart4 with rts and cts ,

the set is as follow. but the imx6sl's rts pin (MX6SL_PAD_SD1_DAT6__UART4_RTS_B) is always high.

whether should I pull it down force or my set is something wrong.

pinctrl_uart4_1: uart4grp-1 {
fsl,pins = <
MX6SL_PAD_SD1_DAT4__UART4_RX_DATA 0x1b0b1
MX6SL_PAD_SD1_DAT5__UART4_TX_DATA 0x1b0b1
MX6SL_PAD_SD1_DAT7__UART4_CTS_B 0x1b0b1
MX6SL_PAD_SD1_DAT6__UART4_RTS_B 0x1b0b1
>;
};

&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart4_1>;
fsl,uart-has-rtscts;
status = "okay";
/* for DTE mode, add below change */
/* fsl,dte-mode; */
/* pinctrl-0 = <&pinctrl_uart4dte_1>; */
};

&usdhc1 {
status = "disabled";
};

Re: imx6sl uart rts/cts

igorpadykov — Mon, 23 Jul 2018 10:47:00 GMT

Hi yan2

UART_RTS direction is output in DTE mode according to

Table 55. UART I/O Configuration vs. Mode i.MX6SL Datasheet
https://www.nxp.com/docs/en/data-sheet/IMX6SLCEC.pdf

so one can try to uncomment dte statement in dts file and check

bit DCEDTE in UARTx_UFCR register.

Best regards
igor
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Re: imx6sl uart rts/cts

yan2anfei — Mon, 23 Jul 2018 13:46:42 GMT

thank you very much.